1. Field of the Invention
The invention relates to voltage rectifier circuits, and more particularly to isolated voltage rectifier circuits.
2. Description of the Related Art
Electrical isolation between primary and secondary circuits may be required in some applications that also require either AC-DC or DC-DC power conversion. One solution is presented in U.S. patent application Ser. No. 12/802,122 filed May 29, 2010 entitled, “Single-Stage AC-to-DC Converter with Isolation and Power Factor Correction” (the “Cuk application”). FIG. 1 illustrates a bridgeless power factor correction (PFC) rectifier introduced in the Cuk application. In FIG. 1, a resonant tank circuit (defined by a combination of Cr1, Cr2, and Lr) used during an ON-time portion of the circuit cycle to achieve zero current switching of the secondary side rectifiers CR1 and CR2 906. However, the dominant source of loss in the Cuk Application is the switching losses caused by the main switch drain capacitance and leakage inductance of the primary transformer.
A need continues to exist to reduce switching losses and primary transformer power losses in isolated power converters.